Exploring the direct synthesis of exchange-spring nanocomposites by reduction of CoFe2O4 spinel nanoparticles using in situ neutron diffraction

In situ neutron powder diffraction (NPD) was employed for investigating gram-scale reduction of hard magnetic CoFe2O4 (spinel) nanoparticles into CoFe2O4/CoFe2 exchange-spring nanocomposites via H2 partial reduction.

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Metal hydride formation in palladium and palladium rich intermetallic compounds studied by in situ neutron diffraction

Powder Diffraction ◽

10.1017/s0885715613001000 ◽

2013 ◽

Vol 28 (S2) ◽

pp. S242-S255 ◽

Cited By ~ 6

Author(s):

H. Kohlmann ◽

N. Kurtzemann ◽

T. C. Hansen

Keyword(s):

Intermetallic Compounds ◽

Powder Diffraction ◽

Neutron Powder Diffraction ◽

Gas Pressure ◽

Type Structure ◽

Sapphire Crystal ◽

Direct Reaction ◽

Β Phase ◽

In Situ Neutron Diffraction

In order to investigate the hydrogenation of intermetallic compounds, a gas pressure cell for in situ neutron powder diffraction based on a sapphire crystal tube was constructed. By proper orientation of the single crystal Bragg peaks of the container material can be avoided, resulting in a very low diffraction background. Using a laser heating and gas pressure controller, the hydrogenation (deuteration) of palladium and palladium rich intermetallics was studied in real time up to 8 MPa gas pressure and 700 K. Crystal structure parameters of palladium deuterides could be obtained under various deuterium gas pressures, corresponding to compositional ranges of 0.04≤x≤0.11 for the α-phase and 0.52≤x≤0.72 for the β-phase at 446 K. In situ neutron powder diffraction of the deuteration of a thallium lead palladium intermetallic Tl1-xPbxPd3 shows two superstructures of the cubic closest packing (ccp) to transform independently into a AuCu3 type structure. This proves a direct reaction to the deuterium filled AuCu3 type structure instead of a reaction cascade involving different ccp superstructures and thus gives new insights into the reaction pathways of palladium rich intermetallic compounds.

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Use of Neutron Diffraction for Describing Texture of Isostatically-Pressed Molybdite Powders

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.105.83 ◽

2005 ◽

Vol 105 ◽

pp. 83-88 ◽

Cited By ~ 1

Author(s):

H. Sitepu ◽

Heinz Günter Brokmeier

Keyword(s):

Crystal Structure ◽

Neutron Diffraction ◽

Powder Diffraction ◽

Quantitative Description ◽

Neutron Powder Diffraction ◽

Powder Diffraction Data ◽

Neutron Powder Diffraction Data ◽

Pole Figures ◽

Diffraction Patterns ◽

Excellent Tool

The modelling and/or describing of texture (i.e. preferred crystallographic orientation (PO)) is of critical importance in powder diffraction analysis - for structural study and phase composition. In the present study, the GSAS Rietveld refinement with generalized spherical harmonic (GSH) was used for describing isostatically-pressed molybdite powders neutron powder diffraction data collected in the ILL D1A instrument. The results showed that for texture in a single ND data of molybdite the reasonable crystal structure parameters may be obtained when applying corrections to intensities using the GSH description. Furthermore, the WIMV method was used to extract the texture description directly from a simultaneous refinement with 1368 whole neutron diffraction patterns taken from the sample held in a variety of orientations in the ILL D1B texture goniometer. The results provided a quantitative description of the texture refined simultaneously with the crystal structure. Finally, the (002) molybdite pole-figures were measured using the GKSS TEX2 texture goniometer. The results showed that neutron diffraction is an excellent tool to investigate the texture in molybdite.

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